v4.19.13 snapshot.
diff --git a/drivers/gpio/gpio-adp5588.c b/drivers/gpio/gpio-adp5588.c
new file mode 100644
index 0000000..da9781a
--- /dev/null
+++ b/drivers/gpio/gpio-adp5588.c
@@ -0,0 +1,499 @@
+/*
+ * GPIO Chip driver for Analog Devices
+ * ADP5588/ADP5587 I/O Expander and QWERTY Keypad Controller
+ *
+ * Copyright 2009-2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/i2c.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+#include <linux/platform_data/adp5588.h>
+
+#define DRV_NAME	"adp5588-gpio"
+
+/*
+ * Early pre 4.0 Silicon required to delay readout by at least 25ms,
+ * since the Event Counter Register updated 25ms after the interrupt
+ * asserted.
+ */
+#define WA_DELAYED_READOUT_REVID(rev)	((rev) < 4)
+
+struct adp5588_gpio {
+	struct i2c_client *client;
+	struct gpio_chip gpio_chip;
+	struct mutex lock;	/* protect cached dir, dat_out */
+	/* protect serialized access to the interrupt controller bus */
+	struct mutex irq_lock;
+	unsigned gpio_start;
+	unsigned irq_base;
+	uint8_t dat_out[3];
+	uint8_t dir[3];
+	uint8_t int_lvl[3];
+	uint8_t int_en[3];
+	uint8_t irq_mask[3];
+	uint8_t irq_stat[3];
+	uint8_t int_input_en[3];
+	uint8_t int_lvl_cached[3];
+};
+
+static int adp5588_gpio_read(struct i2c_client *client, u8 reg)
+{
+	int ret = i2c_smbus_read_byte_data(client, reg);
+
+	if (ret < 0)
+		dev_err(&client->dev, "Read Error\n");
+
+	return ret;
+}
+
+static int adp5588_gpio_write(struct i2c_client *client, u8 reg, u8 val)
+{
+	int ret = i2c_smbus_write_byte_data(client, reg, val);
+
+	if (ret < 0)
+		dev_err(&client->dev, "Write Error\n");
+
+	return ret;
+}
+
+static int adp5588_gpio_get_value(struct gpio_chip *chip, unsigned off)
+{
+	struct adp5588_gpio *dev = gpiochip_get_data(chip);
+	unsigned bank = ADP5588_BANK(off);
+	unsigned bit = ADP5588_BIT(off);
+	int val;
+
+	mutex_lock(&dev->lock);
+
+	if (dev->dir[bank] & bit)
+		val = dev->dat_out[bank];
+	else
+		val = adp5588_gpio_read(dev->client, GPIO_DAT_STAT1 + bank);
+
+	mutex_unlock(&dev->lock);
+
+	return !!(val & bit);
+}
+
+static void adp5588_gpio_set_value(struct gpio_chip *chip,
+				   unsigned off, int val)
+{
+	unsigned bank, bit;
+	struct adp5588_gpio *dev = gpiochip_get_data(chip);
+
+	bank = ADP5588_BANK(off);
+	bit = ADP5588_BIT(off);
+
+	mutex_lock(&dev->lock);
+	if (val)
+		dev->dat_out[bank] |= bit;
+	else
+		dev->dat_out[bank] &= ~bit;
+
+	adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
+			   dev->dat_out[bank]);
+	mutex_unlock(&dev->lock);
+}
+
+static int adp5588_gpio_direction_input(struct gpio_chip *chip, unsigned off)
+{
+	int ret;
+	unsigned bank;
+	struct adp5588_gpio *dev = gpiochip_get_data(chip);
+
+	bank = ADP5588_BANK(off);
+
+	mutex_lock(&dev->lock);
+	dev->dir[bank] &= ~ADP5588_BIT(off);
+	ret = adp5588_gpio_write(dev->client, GPIO_DIR1 + bank, dev->dir[bank]);
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+static int adp5588_gpio_direction_output(struct gpio_chip *chip,
+					 unsigned off, int val)
+{
+	int ret;
+	unsigned bank, bit;
+	struct adp5588_gpio *dev = gpiochip_get_data(chip);
+
+	bank = ADP5588_BANK(off);
+	bit = ADP5588_BIT(off);
+
+	mutex_lock(&dev->lock);
+	dev->dir[bank] |= bit;
+
+	if (val)
+		dev->dat_out[bank] |= bit;
+	else
+		dev->dat_out[bank] &= ~bit;
+
+	ret = adp5588_gpio_write(dev->client, GPIO_DAT_OUT1 + bank,
+				 dev->dat_out[bank]);
+	ret |= adp5588_gpio_write(dev->client, GPIO_DIR1 + bank,
+				 dev->dir[bank]);
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_GPIO_ADP5588_IRQ
+static int adp5588_gpio_to_irq(struct gpio_chip *chip, unsigned off)
+{
+	struct adp5588_gpio *dev = gpiochip_get_data(chip);
+
+	return dev->irq_base + off;
+}
+
+static void adp5588_irq_bus_lock(struct irq_data *d)
+{
+	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
+
+	mutex_lock(&dev->irq_lock);
+}
+
+ /*
+  * genirq core code can issue chip->mask/unmask from atomic context.
+  * This doesn't work for slow busses where an access needs to sleep.
+  * bus_sync_unlock() is therefore called outside the atomic context,
+  * syncs the current irq mask state with the slow external controller
+  * and unlocks the bus.
+  */
+
+static void adp5588_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
+	int i;
+
+	for (i = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
+		if (dev->int_input_en[i]) {
+			mutex_lock(&dev->lock);
+			dev->dir[i] &= ~dev->int_input_en[i];
+			dev->int_input_en[i] = 0;
+			adp5588_gpio_write(dev->client, GPIO_DIR1 + i,
+					   dev->dir[i]);
+			mutex_unlock(&dev->lock);
+		}
+
+		if (dev->int_lvl_cached[i] != dev->int_lvl[i]) {
+			dev->int_lvl_cached[i] = dev->int_lvl[i];
+			adp5588_gpio_write(dev->client, GPIO_INT_LVL1 + i,
+					   dev->int_lvl[i]);
+		}
+
+		if (dev->int_en[i] ^ dev->irq_mask[i]) {
+			dev->int_en[i] = dev->irq_mask[i];
+			adp5588_gpio_write(dev->client, GPIO_INT_EN1 + i,
+					   dev->int_en[i]);
+		}
+	}
+
+	mutex_unlock(&dev->irq_lock);
+}
+
+static void adp5588_irq_mask(struct irq_data *d)
+{
+	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
+	unsigned gpio = d->irq - dev->irq_base;
+
+	dev->irq_mask[ADP5588_BANK(gpio)] &= ~ADP5588_BIT(gpio);
+}
+
+static void adp5588_irq_unmask(struct irq_data *d)
+{
+	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
+	unsigned gpio = d->irq - dev->irq_base;
+
+	dev->irq_mask[ADP5588_BANK(gpio)] |= ADP5588_BIT(gpio);
+}
+
+static int adp5588_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct adp5588_gpio *dev = irq_data_get_irq_chip_data(d);
+	uint16_t gpio = d->irq - dev->irq_base;
+	unsigned bank, bit;
+
+	if ((type & IRQ_TYPE_EDGE_BOTH)) {
+		dev_err(&dev->client->dev, "irq %d: unsupported type %d\n",
+			d->irq, type);
+		return -EINVAL;
+	}
+
+	bank = ADP5588_BANK(gpio);
+	bit = ADP5588_BIT(gpio);
+
+	if (type & IRQ_TYPE_LEVEL_HIGH)
+		dev->int_lvl[bank] |= bit;
+	else if (type & IRQ_TYPE_LEVEL_LOW)
+		dev->int_lvl[bank] &= ~bit;
+	else
+		return -EINVAL;
+
+	dev->int_input_en[bank] |= bit;
+
+	return 0;
+}
+
+static struct irq_chip adp5588_irq_chip = {
+	.name			= "adp5588",
+	.irq_mask		= adp5588_irq_mask,
+	.irq_unmask		= adp5588_irq_unmask,
+	.irq_bus_lock		= adp5588_irq_bus_lock,
+	.irq_bus_sync_unlock	= adp5588_irq_bus_sync_unlock,
+	.irq_set_type		= adp5588_irq_set_type,
+};
+
+static int adp5588_gpio_read_intstat(struct i2c_client *client, u8 *buf)
+{
+	int ret = i2c_smbus_read_i2c_block_data(client, GPIO_INT_STAT1, 3, buf);
+
+	if (ret < 0)
+		dev_err(&client->dev, "Read INT_STAT Error\n");
+
+	return ret;
+}
+
+static irqreturn_t adp5588_irq_handler(int irq, void *devid)
+{
+	struct adp5588_gpio *dev = devid;
+	unsigned status, bank, bit, pending;
+	int ret;
+	status = adp5588_gpio_read(dev->client, INT_STAT);
+
+	if (status & ADP5588_GPI_INT) {
+		ret = adp5588_gpio_read_intstat(dev->client, dev->irq_stat);
+		if (ret < 0)
+			memset(dev->irq_stat, 0, ARRAY_SIZE(dev->irq_stat));
+
+		for (bank = 0, bit = 0; bank <= ADP5588_BANK(ADP5588_MAXGPIO);
+			bank++, bit = 0) {
+			pending = dev->irq_stat[bank] & dev->irq_mask[bank];
+
+			while (pending) {
+				if (pending & (1 << bit)) {
+					handle_nested_irq(dev->irq_base +
+							  (bank << 3) + bit);
+					pending &= ~(1 << bit);
+
+				}
+				bit++;
+			}
+		}
+	}
+
+	adp5588_gpio_write(dev->client, INT_STAT, status); /* Status is W1C */
+
+	return IRQ_HANDLED;
+}
+
+static int adp5588_irq_setup(struct adp5588_gpio *dev)
+{
+	struct i2c_client *client = dev->client;
+	struct adp5588_gpio_platform_data *pdata =
+			dev_get_platdata(&client->dev);
+	unsigned gpio;
+	int ret;
+
+	adp5588_gpio_write(client, CFG, ADP5588_AUTO_INC);
+	adp5588_gpio_write(client, INT_STAT, -1); /* status is W1C */
+	adp5588_gpio_read_intstat(client, dev->irq_stat); /* read to clear */
+
+	dev->irq_base = pdata->irq_base;
+	mutex_init(&dev->irq_lock);
+
+	for (gpio = 0; gpio < dev->gpio_chip.ngpio; gpio++) {
+		int irq = gpio + dev->irq_base;
+		irq_set_chip_data(irq, dev);
+		irq_set_chip_and_handler(irq, &adp5588_irq_chip,
+					 handle_level_irq);
+		irq_set_nested_thread(irq, 1);
+		irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);
+	}
+
+	ret = request_threaded_irq(client->irq,
+				   NULL,
+				   adp5588_irq_handler,
+				   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				   dev_name(&client->dev), dev);
+	if (ret) {
+		dev_err(&client->dev, "failed to request irq %d\n",
+			client->irq);
+		goto out;
+	}
+
+	dev->gpio_chip.to_irq = adp5588_gpio_to_irq;
+	adp5588_gpio_write(client, CFG,
+		ADP5588_AUTO_INC | ADP5588_INT_CFG | ADP5588_GPI_INT);
+
+	return 0;
+
+out:
+	dev->irq_base = 0;
+	return ret;
+}
+
+static void adp5588_irq_teardown(struct adp5588_gpio *dev)
+{
+	if (dev->irq_base)
+		free_irq(dev->client->irq, dev);
+}
+
+#else
+static int adp5588_irq_setup(struct adp5588_gpio *dev)
+{
+	struct i2c_client *client = dev->client;
+	dev_warn(&client->dev, "interrupt support not compiled in\n");
+
+	return 0;
+}
+
+static void adp5588_irq_teardown(struct adp5588_gpio *dev)
+{
+}
+#endif /* CONFIG_GPIO_ADP5588_IRQ */
+
+static int adp5588_gpio_probe(struct i2c_client *client,
+					const struct i2c_device_id *id)
+{
+	struct adp5588_gpio_platform_data *pdata =
+			dev_get_platdata(&client->dev);
+	struct adp5588_gpio *dev;
+	struct gpio_chip *gc;
+	int ret, i, revid;
+
+	if (!pdata) {
+		dev_err(&client->dev, "missing platform data\n");
+		return -ENODEV;
+	}
+
+	if (!i2c_check_functionality(client->adapter,
+					I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
+		return -EIO;
+	}
+
+	dev = devm_kzalloc(&client->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->client = client;
+
+	gc = &dev->gpio_chip;
+	gc->direction_input = adp5588_gpio_direction_input;
+	gc->direction_output = adp5588_gpio_direction_output;
+	gc->get = adp5588_gpio_get_value;
+	gc->set = adp5588_gpio_set_value;
+	gc->can_sleep = true;
+
+	gc->base = pdata->gpio_start;
+	gc->ngpio = ADP5588_MAXGPIO;
+	gc->label = client->name;
+	gc->owner = THIS_MODULE;
+	gc->names = pdata->names;
+
+	mutex_init(&dev->lock);
+
+	ret = adp5588_gpio_read(dev->client, DEV_ID);
+	if (ret < 0)
+		goto err;
+
+	revid = ret & ADP5588_DEVICE_ID_MASK;
+
+	for (i = 0, ret = 0; i <= ADP5588_BANK(ADP5588_MAXGPIO); i++) {
+		dev->dat_out[i] = adp5588_gpio_read(client, GPIO_DAT_OUT1 + i);
+		dev->dir[i] = adp5588_gpio_read(client, GPIO_DIR1 + i);
+		ret |= adp5588_gpio_write(client, KP_GPIO1 + i, 0);
+		ret |= adp5588_gpio_write(client, GPIO_PULL1 + i,
+				(pdata->pullup_dis_mask >> (8 * i)) & 0xFF);
+		ret |= adp5588_gpio_write(client, GPIO_INT_EN1 + i, 0);
+		if (ret)
+			goto err;
+	}
+
+	if (pdata->irq_base) {
+		if (WA_DELAYED_READOUT_REVID(revid)) {
+			dev_warn(&client->dev, "GPIO int not supported\n");
+		} else {
+			ret = adp5588_irq_setup(dev);
+			if (ret)
+				goto err;
+		}
+	}
+
+	ret = devm_gpiochip_add_data(&client->dev, &dev->gpio_chip, dev);
+	if (ret)
+		goto err_irq;
+
+	dev_info(&client->dev, "IRQ Base: %d Rev.: %d\n",
+			pdata->irq_base, revid);
+
+	if (pdata->setup) {
+		ret = pdata->setup(client, gc->base, gc->ngpio, pdata->context);
+		if (ret < 0)
+			dev_warn(&client->dev, "setup failed, %d\n", ret);
+	}
+
+	i2c_set_clientdata(client, dev);
+
+	return 0;
+
+err_irq:
+	adp5588_irq_teardown(dev);
+err:
+	return ret;
+}
+
+static int adp5588_gpio_remove(struct i2c_client *client)
+{
+	struct adp5588_gpio_platform_data *pdata =
+			dev_get_platdata(&client->dev);
+	struct adp5588_gpio *dev = i2c_get_clientdata(client);
+	int ret;
+
+	if (pdata->teardown) {
+		ret = pdata->teardown(client,
+				      dev->gpio_chip.base, dev->gpio_chip.ngpio,
+				      pdata->context);
+		if (ret < 0) {
+			dev_err(&client->dev, "teardown failed %d\n", ret);
+			return ret;
+		}
+	}
+
+	if (dev->irq_base)
+		free_irq(dev->client->irq, dev);
+
+	return 0;
+}
+
+static const struct i2c_device_id adp5588_gpio_id[] = {
+	{DRV_NAME, 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, adp5588_gpio_id);
+
+static struct i2c_driver adp5588_gpio_driver = {
+	.driver = {
+		   .name = DRV_NAME,
+		   },
+	.probe = adp5588_gpio_probe,
+	.remove = adp5588_gpio_remove,
+	.id_table = adp5588_gpio_id,
+};
+
+module_i2c_driver(adp5588_gpio_driver);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("GPIO ADP5588 Driver");
+MODULE_LICENSE("GPL");